P0478 JEEP High Voltage On The Engine Brake Driver

Possible causes
– Faulty Engine Brake Driver Relay
– Engine Brake Driver harness is open or shorted
– Engine Brake Driver circuit poor electrical connection
When is the code detected?
The Engine Control Module (ECM) has detected that the signal from the engine brake driver output does not match the driver feedback signal.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)